Compounding Climate and Social Hazards Result in Different Migration Patterns around the World

Written by
Hannah Reynolds/Center for Policy Research on Energy and the Environment
Nov. 28, 2022

In agricultural communities, migration patterns are affected by the collective impacts of climate-related droughts and existing social vulnerabilities, often increasing migration within countries but also potentially limiting options for long-range, international migration. 

Extreme drought related to climate change holds serious consequences for vulnerable communities, especially those who rely on agriculture for their livelihoods. When droughts become sustained, additional climate disasters hit, and/or existing social vulnerabilities exacerbate the impacts of drought – also known as compound events – a population’s ability to adapt to periods of drought can be impeded. While popular discussions of “climate migrants” provide an overly simplistic view that millions of people will begin moving in response to climate change, Princeton University research demonstrates that the situation is far more nuanced.

A new study published in the journal iScience uses a unique multi-method approach to show how a combination of drought events and social vulnerability factors such as poverty, food insecurity, pandemic, and unemployment affect human migration patterns in three drought-prone countries. They find substantial differences in how people in Mexico, Madagascar, and Nepal respond to drought, based on different types of existing, context-specific vulnerabilities for populations in each location. Most importantly, their research highlights that exposure to climate hazards like drought is not the only factor affecting migration choices – rather, their research approach allows them to disentangle how other socio-economic factors also influence mobility.

Filiz in blue shirt

Filiz Garip

“The main take-away from comparing three different countries is the importance of context," said Filiz Garip, professor of Sociology and Public Affairs at Princeton University and an author of the study. "The impact of climate change on migration will not be uniform around the globe; it will depend on the vulnerabilities and available resources in each setting. In other words, there are things we can do to give people the option to stay where they are," Garip said.

Nicholas Choquette-Levy

Nicolas Choquette-Levy

“Our study contributes to a growing body of literature that shows that climate migration outcomes are multifaceted,” said Nicolas Choquette-Levy, a Ph.D. candidate at the Princeton School of Public and International Affairs and an author of the study. “There are some cases in which climate change might increase long-range migration, but in a lot of cases, international migration might decrease because existing social vulnerabilities prevent farmers from accumulating the resources needed to migrate overseas,” Choquette-Levy said.

The researchers found that between 1991 and 2018, for instance, internal migration from regions in Mexico with low irrigation access increased significantly (by an additional 14–24 percentage points) in the presence of consecutive droughts. A similar increase (by an additional 2–15 percentage points) is predicted to take place in Nepal if it is subject to compound droughts in the coming years. By contrast, limited road and water infrastructure in southern Madagascar, combined with Covid-related lockdowns, restricted pastoralists from using internal migration as a way to cope with the severe 2019-2020 drought – exacerbating food insecurity in that region. 

Understanding compound events and risk associated with drought can support an approach of preemptive humanitarian action in places with particularly vulnerable populations. Specific policies can be developed to support climate resilience, depending on the unique political, environmental, and socioeconomic contexts of a given location. For example, the researchers suggest that expanding access to accurate information about job opportunities and climate forecasts in Nepal could help people there make more informed choices regarding whether to migrate. In Mexico, investing in community irrigation systems could help more people impacted by compound droughts build resilience where they are, demonstrating the value of preemptive investment in communities before drought hits. In Madgascar, long-term investments in road and water infrastructure, along with improved early-warning systems for future droughts, can provide pastoralists with more options to prepare for looming droughts and to reduce poverty related to drought.

lisa thalheimer
Lisa Thalheimer. Photo credit: Egan Jimenez

“Our study can help policymakers consider where to proactively support the populations that will be worst affected by drought, with an eye towards long-term resilience,” said Lisa Thalheimer, a recent postdoctoral research associate at Princeton’s Center for Policy Research on Energy and the Environment. “When you deal with a climate disaster after the fact, adaptation is more costly. If we take the early warning signs from weather forecasts of an unfolding drought into consideration, we know the places that are most vulnerable in advance. We can then provide support before the droughts get bad, equipping communities with the resources to deal with the drought once it comes,” Thalheimer said.

“The science is pretty clear that in most cases, droughts will become more frequent and more severe,” Choquette-Levy said. “Migration is not necessarily a negative action – it can also be a positive and necessary strategy to help more people cope with climate change. Better access to information about climate impacts can encourage proactive planning so that when migration does occur, it results in the best possible outcomes for building climate resilience.”

This study offers policymakers and other social scientists a way to think about climate migration and disaster relief more realistically. The findings add to a growing body of literature that seeks to help policymakers better understand the different tools to support adaptation and migration, whether long-term or within a single cropping system, as nuanced and necessary steps toward building climate resilience in areas impacted by drought and compounding climate impacts.


The paper, “Compound impacts from droughts and structural vulnerability on human mobility,” was published on November 23, 2022 in iScience. The authors are Lisa Thalheimer, Nicolas Choquette-Levy, and Filiz Garip from Princeton University’s School of Public and International Affairs.